This invention relates to a cutting roller for a mining machine. More particularly, the invention relates to a spraying nozzle arrangement for spraying liquid on the bits located on the periphery of the cutting roller.
The prior art involves cutting rollers for mining machines used in underground mining, particularly for use in coal mining. Cutting rollers of this kind usually consist of a cylindrical tubular housing or body on which one or more cutting blades is or are welded so as to extend helically about the tubular housing. Welded to the outside of the blades at regular intervals are bit holders in which cutter bits are mounted. The end of the cutting roller facing towards the face of the workings is closed off by an end plate.
The known cutting rollers are equipped with spraying nozzles which are installed by means of screw threads in so-called nozzle inserts which are, for example, made out of material under trademark NIROSTA. These nozzle inserts are welded to the blades or closure ring so as to form a one-piece item therewith. The spraying nozzles may be enclosed with nozzle shields which are usually designed as rings extended outwardly from the nozzles, these rings being made out of wear-resistive steel because they are exposed to abrasive minerals.
The disadvantage of these otherwise satisfactory spraying nozzle arrangements is that the nozzle shields of the prior art wear out quickly due to their constant exposure to mineral mined and thus to constant relatively high resistance to mineral particles discharged. Particularly disadvantageous is the fact that in a circular space, in which the nozzle head is located, dust, liquid and rock chips may be collected which can prevent the spraying nozzles from proper functioning. Furthermore, the prior art arrangements make it impossible to clean nozzle shields of individual nozzles during operation. All commercially available spraying nozzle arrangements for cutting rollers utilized for underground mining possess the aforementioned disadvantages.